Billy (33) has spent more than 20 years living on the streets, most of which he has spent addicted to heroin.

Dressed in a grubby yellow hoodie and with bloodstains on his socks from his morning injection, he looks like many other drug addicts.

The dad-of-two, who hails from London, is polite and well-spoken. He made his way to Dublin for romance more than 15 years ago.

"I have been on the streets since the age of 13. The way I found my way over here was I followed a girl over ... for my sins," he says with a laugh.

"I started doing crack when I was 12, it hasn't always been heroin. I grew up with a very addictive personality."

He sleeps in hostels most nights but, in his own words, he has managed to "fluff up" a chance at a rolling booking which would see him with a secure bed in a hostel.

He injects heroin and 'snow blow' (mephedrone), and begs for money to earn enough to pay for his habit. A bag of heroin costs between €15 and €20 but a bag of mephedrone will set him back €25 per day.

"I normally cut the whole bag up and separate it into two hits but there's a lot of people who just do the whole bag," he says.

His drug taking begins early.

"I try to make sure that I have money for a bag [of heroin] first thing in the morning so that way I'm not sick," he says.

Sickness

"Everybody's sickness is different, you know. The way I feel when I'm sick is not necessarily the same way another person would feel when they're sick.

"It's more physical than mental - that's with the heroin anyway," he says. "With snow-blow there's a big mental side as well. It's easy to convince yourself you're not going to use it again. I've had conversations with myself saying that I'm not going to do that again," he says.

At the moment, Billy is injecting two bags of heroin daily, usually one in the morning and one in the evenings. In between, he injects mephedrone which is an upper but, unlike many drug users, he does not take pills or use other drugs. As a service user at the Ana Liffey Drug Project, he visits the drop-in service every day.

The project is campaigning to have medically-supervised injecting centres legalised so that people like Billy will have somewhere safe to inject. He says that he would use the centres.

At the moment he is injecting in public, mostly down laneways in the city centre. The need to inject is urgent once you have drugs, he says.

"You sort of suss out the areas in terms of how quick you can get there. You try not to use anywhere where there is a community living like an estate or anywhere where there could be kids."

As a father, he says he wouldn't like his children to see him or anyone else shoot up.

"You have those days when you just don't care as long as you get it into you," he says about injecting in public.

Care

"Sometimes you have those state of minds when you think about how your life is suffering and how you're affecting the people around you, whether you know them or not."

Billy 'taps-up' on a north Dublin Street. He begs for money but he feels that people respect him more than most homeless people because he scribes a poem on the pavement.

It reads: "The only time you should look down on someone is when you are helping them up. I'm homeless people look down on me, so help me rest my weary head on something more than a concrete bed."

Every morning, Billy taps-up enough money to buy the jumbo chalk sticks that he needs and he is fiercely proud of his handiwork - asking people politely to walk around it.

Living on the streets has landed Billy in trouble and he has spent time in jail. He also has a habit of forgetting to turn up to court dates.

It is easier to find a bed at night time, he has noticed new faces on the street but also more beds opening up.

"But that's come at the price of someone's life, hasn't it," he comments.

Billy is referring to homeless man Jonathan Corrie, who died tragically in December in a doorway just steps from Leinster House.

His death sparked a backlash and a rush of emergency actions to tackle the homeless crisis. Billy was with Jonathan the night before he passed away.

"I would have helped him and he helped me get through a lot of stuff. There's a person I would have been able to call a friend," he says.